Dial controlled signaling system



Apri14, 1944.`

J. T. NEISWINTER DIAL CONTROLLE'SIGALING SYSTEM Filed March 2l, 1942VNSQMRQ. MESSE? .mbv

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INVENTOB J /Vzswznzzer BWK, I ATTORNEY A Patented Apr. 4, 1944 DIALCONTROLLD SIGNALING SYSTEM James T. Neiswinter, South Orange, N. J., as-

signor to American Telephone and Telegraph Company, a corporation of NewYork Application March 21, 1942, Serial No. 435,658 4 Claims. (Cl.177-380) This invention relates to signaling systems and moreparticularly to dial operated signalin systems.

In prior signaling systems, such as telegraph systems, it has been thepractice to use a manually controlled device such as a key to interrupta circuit for the purpose of transmitting a marking or spacing pulse toa distant point. A

. long pulse could be obtained, for example, by

holding the key closed for a long period of time and a shorter pulseobtained by holding the key closed for a briefer interval of time. Ineither case the length of the pulse was dependent upon the judgment andskill of the operator. Accuracy in the timing of the pulses wastherefore dillicult to obtain.

According to the present invention it is proposed to provide apulsing'system for signaling apparatus in which the lengths of thepulses are more accurately determined. To accomplish this end, a dial ofthe type generally employed in the telephone plant is used together witha relay the winding of which is connected in series with the signaling`line, the relay being maintained normally operated. The armature andcontact of the relay are so connected as to provide a circuit in shuntwith the lso-called off-normal paratus TTY, the line L1 extending to adistant station which may include,` for example, a switching apparatusSA controlled by the pulses produced by the dial apparatus TDA. Theswitching apparatus SA may be employed to connect line L1 to anyone of aplurality of lines Lz-Li so that teletypewriter signals may betransmitted in both directions between the teletypewriter TTY and theteletypewriter apparatus (not shown) connected to the selected line.

Itwill be observed that when the dial D is in its normal position asshown in the drawing, current flows from battery B over line L1 andthroughy the winding of relay R, the completed circuit including batteryB, the lower conductor of line L1, the off-normal contacts K1, thewinding of relay R, the pulsing contacts K2, the teleto the numberdialed. The pulse produced by dialing the digit 2 will be longer thanthat obtained by dialing digit 1, the pulse obtained by dialingdiglt 3will be longer than that obtained Aby dialing digit 2 and so on, thelongest pulse being obtained bydialing the digit 0.

This invention will be better understood from the more detaileddescription hereinafter following when read in connection with theaccompanying drawing showing one embodiment of the invention merely forthe purpose of illustration.

Referring to the drawing the telephone dial apparatus TDA-Which may be,for example, a standard telephone dial-includes the usual rotary dialelement D,-the off-normal contacts K1 and the pulsing contacts K2. Otherportions of the dial apparatus such as the governor, etc., which are notrequired for an understanding of the invention are not shown. Thecontacts K1 and K2 are connected in series with the winding of a relayR. This series circuit is connected to a line L1 through ateletypewriter aptypewriter TTY, the upper conductor of line L1 and theapparatus SA. This current is sufficient to maintain relay R -in anoperated condition. When relay R is so operated, its armature and makecontact provide a circuit in shunt with the off-normal contacts K1.Hence when dial D is rotated in a clockwise direction, the off-normalcontacts K1 will be opened, but theV circuitA from battery B to thewinding of relay R will be held closed through the parallel circuitcompleted through the armature and 'make contact of relay R. Thecontacts' K1 are held opened at all times when the dial D is not in thenormal position shown in 'the drawing, but relay R will remain operateduntil the pulsing contacts K2 become opened.

Upon the release of dial D by the operator, the dial D will then rotatein a counter-clockwise direction in the usual manner, thereby causingthe pulsing contacts K2 to open and close repeatedly. The number oftimes that contacts K2 are opened and closed depends directly upon thenumber dialed. Upon the first opening of contacts K2, the circuitinterconnecting battery B with the winding of relay R will be opened andtherefore relay R will release. The release of relay R removes theparallel path previously established by'its armature and contact aroundthe off-normal contacts Ka. Hence theline L1 will become openedimmediately after dial D is released and thus a spacing pulse will betransmitted over line L1 to the apparatus SA.

The line L1 will remain open until the dial D returns to its normalposition shown in the drawing. When the dial D-reaches its normalposition, contacts -K1 will then become closed and contacts K: willcease to open and therefore the latter contacts will remain closed. TheWinding of relay R will then become re-energized, re-

lestablishing a parallel path around the contacts K1. Consequently, theline L1 will become closed.

The length of the spacing signal sent by dial D over the twowire line L1to the distant apparatus SA is measured by the time interval between theinstant when the dial D is released to rotate in a counter-clockwisedirection and the instant when dial D lnally reaches its ncrmalposition. This period of time is determined only by the number dialed.It does not depend cn the discretion vor judgment of the operator. Thelength of the spacing signal will then be accurately timed and-the samesignal maybe repeated as often as desired.

It will be clear that the dial D may be operated to provide any desirednumber of accurately timed spacing pulses or signals of any desiredlengths all interspersed with marking pulses or signals. These differentpulses may be transmitted to control, for example, switching apparatusSA which may be of the type disclosed in my copend'ing applications,Serial Nos. 373,573 and 373,574, led January 8, 1941. In these copendingapplications, the received pulses are employed to select any one of aplurality of diiierentlines such as L2-L4 for the transmission ofteletypewriter or other signals thereover. The teletypewriter TTY maythen be employed for the transmission of signals to and the reception ofsignals from the distant station.

It will be understood, of course, that the apparatus SA may be anywell-known telegraph or other translating device which is suitable torespond to pulses of current received over line L1.

The dial-controlled spacing pulses obtained byl operating a dial such asD may be made longer than those possible with a teletypewritercharacter. This permits the use of slower acting relays and lesscritical timing circuits at the switching apparatus SA. Moreover, thepossibility of false operation is reduced.

While this invention has been shown and described in a particulararrangementmerely for the purpose of illustration, it will be understoodthat the general principles of this invention may be applied to otherandwidely varied organiza. tions without departing from the spirit of theinvention and the scope of the appended claims.

What is claimed is:

1. Apparatus for producing pulses of current comprising a dial-operateddevice having oinormal contacts and pulsing contacts, a normallyoperated relay having its winding in series with both of said contacts,the armature o! said relay being connected so as to providev a path inparallel with said oir-normal contacts, and means for rotating said dialdevice to release said relay for a period of time which is' determinedby the number dialed.

2. Apparatus for producing pulses of current comprising a rotary device,first and second contacts controlled by said rotary device, a normallyoperated relay having its winding connected in series with both saidflrst and second contacts, the armature of said relay being connected soas to provide apath in parallel to said first contact, said rst contactbeing open when said rotary device is not in its normal position, saidrotary device including means whereby said second contact will besuccessively opened and closed when said rotary device is rotated in apredetermined direction, and means for rotating said rotary device torelease said relay for a period of time which is determined by the anglethrough which said rotary device is rotated.

3. Apparatus for producing pulses of current' comprising a rotarydevice, a first contact which is open when said device is not in itsnormal position, said rotary device including a second contact and meanswhereby said second contactv is successively opened and closed when saiddevice is rotated in a predetermined direction, the number of times saidsecond contact is opened andclosed depending on the angle through whichsaid device is rotated in said predetermined direction, a normallyoperated relay having its winding connected in series with both saidfirst and second contacts, the armature of said relay and its contactbeing connected so as to provide a path in parallel with saidrstcontact, and means' for rotating said device in said predetermineddirection to releasesaid relay for a period of time which corres-pondsto the angle through which said device is rotated.

4. Apparatus for producing pulses of current for transmission over a.two-wire line, comprising a telephone dial having oirnormal contacts andpulsing contacts, a normally operated relay having its winding connectedin series with both of said contacts and said line, the armature andcontact of said relay being connected so as to provide a path inparallel with said off-normal contacts, and means for rotating said dialto release said relay to establish a pulse of a length which isdependent upon the number dialed by said dial.

JAMES T. NEISWINTER.

